[Zurück]

M.-A. Néouze:
"Ionic Nanoparticle Networks";
Vortrag: Laboratoire de Chimie de la Matiére Condensée, Collége de France; Paris; France (eingeladen); 17.05.2011.

Recently we published the synthesis of new hybrid materials, Ionic Nanoparticles Networks (INN), made of nanoparticles covalently connected by organic bridging ligands owing to a "click chemistry-like" reaction. The original method we developed to synthesize 3-D networks is based on the functionalization of metal oxide nanoparticles with ionic linkers, the bridging ligands containing imidazolium units. Those new inorganic-organic hybrid materials are promising candidates for many applications such as catalysis or electrolytes.
The length and rigidity of the imidazolium bridging units was varied. The short-range order of the network was investigated via small-angle X-ray scattering. This short-range order was interpreted as originating from self-organization of the aromatic rings of the ligands bridging the nanoparticles by means of -stacking. This hypothesis was validated by luminescence investigations on the hybrid materials. The photoluminescence experiments revealed strongly enhanced emission in the hybrid material in comparison with neat imidazolium salts.

Anion metathesis reactions were performed on ionic silica networks based on imidazolium chloride bridging units. The investigated salts were NaBF4, KPF6 and LiN(SO2CF3)2. X-ray diffraction experiments and Nuclear Magnetic Resonance analysis allowed following the anion metathesis. The anion metathesis reaction provides a tailoring tool for the hybrid material hydrophilicity.

Besides the methodology was extended towards the formation of hybrid material thin films using a layer-by-layer deposition method for the formation of imidazolium-based assemblies of photocatalytic titania nanoparticles. This provides a new route for the controlled processing of this promising class of materials.

Projektleitung Marie-Alexandra Néouze:
Ionische Verknüpfung von Nanopartikeln